Chair frame



FIG. 1 is a perspective view of the chair frame showing my new design;

FIG. 2 is a front elevational view of the chair frame;

FIG. 3 is a right side elevational view of the chair frame, the opposite side being a mirror image thereof; and

FIG. 4 is a rear elevational view of the chair frame. 

The ornamental design for a chair frame, as shown and described. 